1. Mix bread flour, caster sugar, and instant sugar in a bowl.2. Make a hole in the center. Add yolks and water. Mix and knead until elastic.3. Add softened butter and salt. Knead again until elastic.4. Put in a lightly greased bowl. Cover with plastic wrap and set aside until doubled (approximately 1 hour). Meanwhile, prepare filling (recipe follows).5. Punch dough down and set aside for 10 minutes. Grease and line a 9-inch round pan.6. On a lightly floured surface, roll dough out into 8 x 8-inch rectangle. Spread filling over dough, leaving 2 cm border on each side.7. Roll dough up. Cut into 1-inch thick slices. Arrange the scrolls on the prepared pan. Cover with plastic wrap and let rise for another 30 minutes.8. Bake on preheated oven at 180 C for 20-25 minutes. Remove from oven and drizzle with icing (recipe follows) while still hot.